fix users association

app/models/game.py

@@ -15,7 +15,7 @@ class Game(db.Model):
         'GamePlayer',
         back_populates='game',
         cascade="save-update, merge, delete, delete-orphan")
-    users = association_proxy('game_players', 'user',
+    users = association_proxy('players', 'user',
         creator=lambda user: GamePlayer(user=user))
     objectives = db.relationship(
         'Objective',